The present invention relates to an absorbent article such as a sanitary napkin, a panty liner or an incontinence pad, which article is intended to be substantially accommodated within the panties of a user and comprising a first absorbent part and a second absorbent part, which two parts are mutually joined.
A basic requirement for an absorbent article such as a sanitary napkin or the like is that the article must be shaped in such a manner that it can collect and absorb all discharged bodily fluid.
Since, for example, sanitary napkins are intended to be accommodated within a pair of normal panties, they are relatively small and, above all, often rather narrow. There is therefore an obvious risk that by misplacing such an article within the panties or by it being deformed during use, it will not present a sufficiently large receiving surface for the discharged bodily fluid.
For example, it is not uncommon that the absorbent article is placed by mistake too far forward or too far backwards or offset somewhat transversely. Another commonly occurring reason for bodily fluid to leak past an absorbent article and to soil the user""s clothing is that the article is compressed between the legs of the user and thus becomes so narrow that the surface available for absorption becomes insufficient. Neither is it unusual for the side edges of the article to become folded over the surface of the article, thereby reducing the available surface.
An absorbent article of the type under consideration is generally maintained in the panties of the user by means of self-adhesive glue and/or a friction coating. When placing the article in the panties, it is difficult to obtain a placement which is optimal in relation to the body of the user. Normally, the crotch portion of the panties is used to determine where the article is to be placed. However, since panties are manufactured in a surprisingly large number of different models and sizes, the position and shape of the central portion provides an extremely unreliable indication of where in the panties an absorbent article should be positioned.
One way to reduce the risk of edge leakage due to deformation of the article during use is to provide the article with a preformed raised portion which, during use, is intended to contact the user is genitals. In this manner, discharged bodily fluid can be intercepted as soon as it exits the user""s body and be immediately absorbed within the article instead of running over its surface. In addition, a raised portion facilitates the placement of the absorbent article by the user in a correct position in relation to the body.
For this purpose, a raised portion of the type which is described in Swedish patent application no. 9604221-3 is particularly suitable. Such a raised portion has a predictable shape both before and during use and it maintains its shape irrespective of the movements of the user and the wetting to which the article is subjected. The raised portion is anatomically shaped, which implies that it is relatively narrow so as to be able to be inserted somewhat between the labia of the user during use without causing discomfort to the user.
Even though such a raised portion functions well for its purpose, it has been shown that should the raised portion be subjected to large quantities of bodily fluid during a relatively short period of time, there is a risk that a quantity of the liquid will run down on the outside of the raised portion and over the side edges of the absorbent article. For example, such leakage can arise when the user of a sanitary napkin has been sitting or lying down for a long period of time and then suddenly gets up. When the user has been sitting or lying down, a relatively large quantity of menstrual fluid may collect in the user""s vagina. As a result of a sudden change in the body position, the entire quantity of collected fluid can be discharged in one go. A narrow raised portion of the type which is described in SE 9604221-3 does not therefore have a sufficiently large surface to be able to receive and absorb the entire quantity of liquid at once, which is why such sudden liquid flows often result in leakage.
However, by means of the present invention an improved absorbent article of the above-mentioned type has been provided in which the risk of leakage has been considerably reduced.
An article in accordance with the invention is primarily characterized in that the article comprises means for obtaining and maintaining an elongate cavity between the second surface of the upper part and the first surface of the lower part, at least in the wetting region which is that region of the article which is intended to initially receive discharged bodily fluid, whereby the upper part and the lower part are separated from each other by a distance of between 0.3 mm and 5 mm in the elongate cavity and that the elongate cavity permits liquid transmission in between the upper part and the lower part. For liquid to be able to enter between the two constituent parts of the article, it is therefore necessary that the edge regions of the parts are maintained at a distance from each other, at least in the wetting region of the article.
According to one embodiment of the invention, the upper part is substantially made from a relatively stiff material and is substantially elongate and presents a first end section and a second end section, whereby the upper part is connected to the lower part solely at the end sections. Furthermore, the lower part comprises a rigid, shape-permanent material layer which has at least the same extension in the principal plane of the article as the upper part, whereby the shape-permanent material layer is curved in the article""s longitudinal direction in a direction away from the upper part, whereby the first surface of the lower part is also curved in a direction away from the upper part, with the second surface of the upper part having a shape such that the article presents a gap between the upper part and the lower part.
In such an embodiment, the elongate cavity is created and maintained by the presence of the curved, shape-permanent material layer as well as by the upper part also having relatively high stiffness. High stiffness in the upper part can be obtained, for example, by using a heavily compressed absorption material or by a particular stiffness-increasing insert of metal, plastic, wood or the like. In addition, the surface on the upper part which faces towards the lower part must be shaped so that it creates a gap between the upper part and the lower part. This implies that the second surface of the upper part can be curved in the same direction as the first surface of the lower part, though with a greater radius of curvature than the lower part. Alternatively, the second surface of the upper part can be completely flat or can be curved in a direction away from the lower part. Combinations of different curvatures within different parts of the curved surfaces are conceivable as long as an elongate cavity is maintained between the two parts, at least within the wetting region of the article.
For example., the shape-permanent material layer can advantageously be curved in a direction away from the upper part in both the longitudinal and the transverse direction of the article, whereby the lower part is bowl-shaped at least in the article""s wetting region and thereby creates a liquid-receiving container under the upper part of the article.
If the shape-permanent material layer is made from liquid impermeable material such as plastic or the like, the shape-permanent material layer can form the liquid impermeable layer of the lower part and thereby form a liquid impermeable bottom layer of the article. Such a shape-permanent, liquid impermeable shell can also be used to give the article a predetermined, anatomically adapted shape.
Considering the comfort of the user, since the shape-permanent material layer is made of a very stiff and hard material, it is suitable that the shape-permanent material layer at least somewhere within the mid portion of the article has a greatest extension in the article""s transverse direction which does not exceed 40 mm, and preferably does not exceed 35 mm.
It can furthermore be suitable to arrange soft, pressure-absorbing deformation zones around at least parts of the article""s side edges.
Another method of attaining a gap-like cavity between the upper and lower parts of the article is by arranging a spacer between the parts. Such a spacer can, for example, be in the form of a snap fastener, a material plate, or the like. The spacer should be substantially unaffected by wetting and at least should not collapse so that the elongate cavity would disappear when the article is being used. Suitable materials for use as such a spacer are, for example, plastics, metal, wood, or absorbent material which swells rather than collapses when wetted.
A further example of a spacer which can be used is a stiffening element arranged substantially perpendicular to the bottom layer of the lower part and which extends from the bottom layer through the lower part and onwards into the upper part.
The upper part can be fixedly attached to the lower part or may be attached to the lower part in a manner which allows the upper part to be released from the lower part. The advantage with the latter embodiment is that it is thereby possible to remove a soiled upper part while reusing the lower part. In addition, the user is given the possibility to determine herself whether she wishes to use the upper part.
In accordance with a further embodiment, the connection between the upper part and the lower part is such that it permits repeated attachment and separation of the two parts. Examples of attachment devices which permits repeatable attachment and separation are hook-and-loop type surfaces, crooks/hooks, loops, buttons, snap fasteners or the like.
In order to provide the absorbent article with an anatomically correct shape it is suitable that the upper part has an extension in the article""s transverse direction which is less than the extension of the lower part in the transverse direction. A particularly advantageous size-ratio is realized if the width of the mid portion of the upper part is between xc2xc and ⅓ of the width of the lower part.
In a corresponding manner, the upper part should have a lesser extension in the longitudinal direction than the lower part and should thereby be between ⅓ and xc2xe of the length of the lower part.
By arranging the two constituent parts of the article at a distance from each other, it is possible in a second absorption stage to collect bodily fluid which flows over the outside of the first part. In this manner, it is avoided that the bodily fluid flows past the edges of the article to thereby result in leakage. Instead, the bodily fluid can flow in under the first part and be absorbed by the absorption material in the second part. It is thereby suitable that the second part of the absorbent article is bowl-shaped or curved in the article""s transverse direction so that the fluid flows under the influence of gravity towards the longitudinal centerline of the article, i.e. in under the first part.